1. Field of the Invention
This invention relates to a component device for optical communication, more particularly, to a component device for optical communication that has a reflector for either emitting or receiving the light to be used in optical communication. Stated more specifically, the invention relates to a lamp that has the optical characteristics necessary for IR data transmission in the space, that can be mounted on a substrate surface and that is thin with a diameter of 5 mm.
2. Background Information
Remote controls as an accessory to TV receivers use IR lamps with a diameter of 3 mm or 5 mm to perform IR carried data transmission in the space. The use of these IR lamps is increasing today. Particularly in the case of performing data communication with computer's peripheral equipment through the space, the increasing reduction in the size of the peripheral equipment has motivated the installation of IR lamps of a smaller size and a greater radiant intensity on the computer.
FIG. 9 shows a prior art case of IR lamp installation on a circuit board 95 on which the lamp 96 is mounted. In the case of a 3 mm.sup..phi. lamp, its height is as small as 5.3 mm but, at the same time, the lamp diameter is so small (3 mm) that the optical axis of the lamp will be offset during assembly which, in turn, will cause an angular offset during optical communication.
In the case of a 5 mm.sup..phi. lamp, the scattering in assembly is comparatively small and will not cause any great offset in the optical axis of the lamp; in addition, the focusing of light by the lamp is so efficient that it is capable of producing high radiant intensity. On the other hand, the height of the lamp exceeds 7 mm, which has been a bottleneck in the effort to realize a compact device.
The primary reason for this problem will be apparent from FIG. 10, in which a light-emitting diode (LED) 92 is shown to be carried on a leadframe 93. In high-volume production of the device, the leadframe 93 has to be embedded in the lens portion 91 of the lamp 94 in order to fix the leadframe in position. This inevitably increases the axial length of the lamp 94.
It is conventional to reduce the height of the lamp 94 by using a leadframe in a thin plate form. However, thin miniature lamps that have the necessary characteristics to meet the requirements for data communication with the computer's peripheral equipment are too costly to warrant their widespread use.